In a power converter, a switching operation is speeded up due to technical innovation of power semiconductors used for a power semiconductor module as a primary component of the power converter, and the loss in the power semiconductors is reduced. Accordingly, a cooler for cooling the power semiconductor module can be reduced in size, and resultantly the size reduction of the power converter is realized. Particularly, a UPS (Uninterruptible Power Supply) having the power converters is installed for data centers in suburbs of cities where land prices are high, therefore, it is required that the installation area is small. In order to effectively use the area of installation, respective power converters in the UPS are installed in a state where side surfaces closely contact one another and rear surfaces closely contact a wall. Accordingly, it is desirable that instruments and parts mounted in the apparatus are accessible from the front of the apparatus in consideration of workability at the time of maintenance.
A power converter for improving workability is known. In Patent Literature 1, a power module unit in which plural semiconductor devices are mounted in a cooling block provided with a cooler such as a cooling fin and a capacitor unit are respectively housed in two sections provided in a casing of the power converter. Accordingly, workability is improved.